Adjustable thermostatic control switch



Sept. 3, 1929.

H. D. MATTHEWS 1,726,748 ADJUSTABLE THERMOSTATIC CONTROL SWITCH Filed July 27, 1926 AT ORN'EY Patented Sept. 3, 1929.

UNITED STATES PATENT OFFICE.

HOWARD D. MATTHEWS, OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELEC- TRIO a MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIEA.

ADJUSTABLE THERMOSTATIC CONTROL SWITCH..

Application filed July 27,

a thermostatic control switch that shall be of simple construction and easily manufacture Another object of my invention is to provide a thermostatic control switch that shall be adapted to actuate the contact members thereof with a snap motion in response to predetermined thermal conditions thereof. Another object of my invention is to provide a thermostatic control switch that shall be adjustable, whereby the contact members thereof may be actuated with a snap motion over a relatively wide range of temperatures. In practising my invention, I provide a pair of supports and a preformed resilient member disposed therebetween. A bimetallic member is adjustably secured to the resilient member at a portion intermediate the ends thereof.

I provide, also, means for varying'the effective distance between the ends of the resilient member, to produce a predetermined deflection therein, in accordance with predetermined thermal conditions, at which the bimetallic member shall be 0 erable to cause the resilient member to de ect laterally be tween the supports with a snap motion. The resilient member is provided with a contact member that is adapted to co-operate' with a stationary contact member, as the resilient member is caused to deflect between the suports in response to thermal conditions of the imetallic member.

By adjusting the relative positions of the bimetallic'member with respect to the resilient 4 member, and by varying the distances between t-heends of the resilient member, the

thermostatic control switch embodying my inventionmay be made to operate in response to a wide range of thermal conditions.

In the single sheet of drawings, Fig. 1 is an elevational view, partially in section, of a device embodying my invention.

Fig. 2 is a v ew, similar to Fig. 1, of a modification of the device illustrated therein; and

Fig. 3 is a side elevation of a modificationof the resilient member employed in the device illustrated in Figs. 1 and 2.

In Fig. 1 of the drawings, a thermostatic control switch 10 is illustrated, which comprises a base member 11, a supporting frame 1926. Serial No. 125,155.

12 secured thereto and a thermo-responsive means 13 disposed between a pair of upwardly extending portions 14 and 15 of the frame member 12.

A contact-supporting member 16'is provided and secured to the base member 11 by suitable means, such as a screw-bolt member 17. A contact member 18 is secured to the member 16 and is adapted to'co-operate with a contact member 19 located on the thermoresponsive member 13.

The thermo-responsive member 13 com prises a resilient member 20 which may pref-- erably be made of spring-steel and a bimetallic member 21, which is secured to the member 20 by screw members 22 and a' securing member 23. The screw members 22 are sojarrang'ed and secured to the members 20 and 21 that the relative positions of these members may be varied in accordance with predetermined thermal conditions, at which the bimetallic member 21 shall be operable to cause engagement or disengagement of the contact members 18 and 19. The member 20 is disposed between a notchedportion'24. of the upwardly extending member M and a notched portion 25 of an adjusting means 26,'which is-located in the upright I portion 15. The member 20 is preshaped to provide curved end portions and 28 and an intermediate curved portion 29 that is curved oppositely to'the end -portions 27 and 28. The degree of curvature of the. intermediate portion 29 may be varied in accordance with the adjustment of the screw members 22.

The adjusting means 26 comprises a screw threaded member 31 and a co-operating refractory member 32 which is ada ted to turn freely in the screw. threaded mem r 31. By turning the screw threaded member 31 towards, or away from, the upright portion 15,

the longitudinal pressure on the resilient member 20 may be varied in accordance with predetermined thermal conditions at which the bimetallic member 21 will-be operable to engage or be disengaged from the contact each other, the longitudinal pressure exerted on the resilient member 20 will be increased, and, if the portions 33 and 34 are separated from each other, the longitudinal pressure exerted on the member 20 will be diminished.

A terminal member 39 extends through the base member 11. and is insulated from the frame member 35 and the base 11 by an insulating bushing4-1'. The ends of the terminal 39 are provided with screw threads whereby nut members 42 and 43 may be employed to maintain the terminal member 39 in its operative position. The contact member 19 is adapted to engage an endportion 44 of the terminal 39. The portion 44 of the terminal 39 may be made of such material as will withstand the corrosive action of anelectric are within reasonable limits;

In Fig. 3 of the drawings, 1 have illustrated a modification of the thermo-responsive. means 13. The thermo-responsive'means 13 comprises a resilient member 45 and a bime, tallic member 46. The bimetallic member 46 is spaced apart from the resilient member 45 by a pair of tubular members 47 and is secured thereto by bolt members 48 which e'xtend through tubular members 47 and are secured in fixed relation thereto by suitable nut members 49. e n

An adjusting means 51 is provided to vary the distance between a portion 52 of the resilient member 45 and the bimetallic member 46. The temperature at which the bime tallic member 46 will be operable to cause the resilient member 45 to deflect laterally between its supports (not'shown), will depend upon the relative position ofthe portion 52 with respect to the bimetallic member 46. A contact member 53 is secured to a portion of the adjusting means-51 which is in engagement with the bimetallic member 46.

The thermostatic control switch illustrated in Figs. 1 and 2, may be adapted to control the circuit of an electric energy translating devicein order tomaintain predetermined means a relatively Wide range of temperatures and which Wlll be positive in its operation.

I provide, also, a resilient member in 'ac thermostatic control switch, having curved end portions of such shape, that when cooperating with a bimetallic thermo-responsive member, the intermediate portion thereof will be deflected to a suitable distance such as will prevent the resilient member from deflecting beyond the center line of its supports.

Since the resilient member is of the shape referred to above, and since itis responsive to the thermal conditions of a bimetallic mem- 1. A thermostat comprising a resilient member supported between two.relatively fixed supports, and abimetallic member extending substantially longitudinally of the resilient member and secured thereto at a predetermined portion of said 1' 'lient member for causing it to deflect laterall thereof with a snap motion when subjected to a predetermined temperature.

2. A thermostat comprising a resilient member supported between two relatively fixed supports, and a bimetallic member adjustably secured to the resilient member for causing it to deflect. laterally thereof with a snap motion when subjected to predetermined temperatures.

3. A thermostat comp-rising a preformed resilient member, means for supporting said resillent member to prevent longitudinal movement thereof, adjusting means for applying a predetermined initial longitudinal stress to said resilient member, and a bimethermal conditions obtainingv in the trans-Vtallic member adjustably secured to the resillatingadevice within safe operating or predetermined limits.

As the bimetallic member 21, illustrated in Figs. 1 and 2, and the bimetallic member 46,

illustrated in Fig. 3, are subjected to an increasing temperature, the changes in curvature thereof will produce such a pressure on the resilient members 2(Land 45 as to cause them to be deflected laterally betweenn-the supports therefor with a snap motion. The contact members co-operating with the thermo-responsive means 13 will be-disengaged or engaged, depending on whether the deflection is away from, or towards, the contact members.

By my invention, I provide a thermostatic switch which may be adjusted to operate over ient member forcausing it to deflect laterally thereof with a snap motion when subjectedto a predetermined temperature.

4. A thermostat comprising a plurality of supports, a resilient member disposed there; between,said resilient member having curved end'portions and an intermediate deformed a portion of opposite curvature to said end portions, and a bimetallic member disposed longitudinally of said resilient member and'secured thereto for causing said resilient mem-- ber to deflect laterally between said supports wlth a snap motion 1n response to predetermined thermal conditions of said bimetallio member. I

5. A thermostat'comprising a plurality of supports, a resilient member disposed therebetween, said resilient member having curved end portions and an intermediate deformed portion of opposite curvature to said end portions, means for applying a predetermined initial longitudinal pressure to said resilient member, and a bimetallic member disposed longitudinally of said resilientmember and secured thereto for causing said resilient member to deflect laterally between said supports with a snap motion in response to redetermined thermal conditions of said bimetallic member.

6. A thermostat comprising a plurality of supports, a resilient member disposed therebetween, said resilient member having curved end portions and an intermediate deformed portion of opposite curvature to said end portions, and a bimetallic member disposed longitudinally of said resilient member and adjustably secured thereto for causing said resilient member to deflect laterally between said supports with a snap motion in response to predetermined thermal conditions of said bimetallic member.

7. A thermostat comprising a plurality of supports, a resilient member disposed-therebetween, said resilient member having curved end portions and an intermediate deformed portion of opposite curvature relative to said end portions, means for applying a predetermined initial longitudinal pressure to said resilient member, and a bimetallic member disposed longitudinally of said resilient member and adjustably secured thereto for causing said resilient member to deflect laterally between said sup orts with a snap motion in response to pretlbtermined thermal conditions of said bimetallic member.

8. A thermostat comprising an elongated resilient member disposed between a air of supports, said resllient member aving curved end portions and an intermediate portion curved oppositely relative to the end portions, and a bimetallic member disposed longitudinally of said resilient member and secured thereto substantially at its ends and at an intermediate portion, the ends of said bimetallic member being adjustably secured relatively to the intermediate portion.

9. A thermostat comprising an elongated resilient member disposed between a pair of supports, said resilient member having curved end portions and an intermediate portion curved oppositely to the end portions, means for applying a predetermined initial longitudinal pressure to said resilient member, and a bimetallic ember disposed longitudinally of said resi ient member and secured thereto substantially at its ends and at an intermediate ortion, the ends of said bimetallic mem er being adjustably secured relatively to the intermediate portion.

10. A thermostat comprising an elongated resilient member disposed between a pair of supports, said resilient member having curved end portions, a bimetallic member disposed longitudinally of said resilient member and secured thereto at a ortion intermediate said curved portions, an means for producing an initial deflection between said bimetallic member and the resilient member.

11. A thermostat comprising an elongated resilient member disposed between a pair of supports, said resilient member having curved end portions, a bimetallic member disposed ,longitudinally of a portion of said resilient member intermediate the curved end portions, and means for securing the ends and an intermediate portion of the bimetallic member to the intermediate portion of the resilient member to produce a predetermined initial deflection therein.

12. A thermostat comprising an elongated resilient member disposed between'a pair of supports, said resilient member havin curved end portions, abimetallic member disposed longitudinally of a portion of said resilient member intermediate the curved end portions, the ends and an intermediate portion thereof being secured in operative relation to the intermediate portion of said resilient member,and adjustable means for producing a. pre determined deflection in said bimetallic member and the intermediate portion of said resilient member. l

13. A thermostat comprising a preformed resilient member, adjustable supportin means for applying a predetermined initia longitudinal stress to said resilient member, a bimetallic strip havin both its ends secured to a redetermine portion of the resilient mem er for causing it to deflect laterally thereof with a snap motion when subjected to a predetermined temperature.

14. A thermostat comprising a resilient member located between a pair of supports, a contact member mounted thereon, a cooperating contact member therefor, and a bimetallic strip secured to and supported entirely by the resilient member for caiising it to deflect laterally between the supports with a snap motion to engage and disengage the contact in accordance with predetermined thermal conditions of the bimetallic strip.

15. A thermostat comprisin a resilient member, a pair of relatively a justable supports operatively engaging the ends of the resilient member to cause it to assume a predetermined sinuous shape, and a bimetallic strip coextensive with a redetermined portion of the resilient mem er and adjustably secured thereto for causing the resilient member to deflect laterally thereof with a sna motion when subjected to predetermined temperature changes.

In testimony whereof, I have hereunto subscribed my name this 16th day of July, 1926.

HOWARD D. MATTHEWS. 

